When a wireless telecommunications service provider receives an incoming call destined for a subscriber of that wireless service provider, the service provider, typically via a mobile switching center (MSC) to a base station controller (BSC) or a radio network controller (RNC), which may be generally referred to herein as a controller, receives the destination telephone number of the subscriber. A typical international wireless destination telephone number comprises a country code and a national mobile number including a national destination code (NDC) and a subscriber number. One or more NDC's are allocated to a public land mobile network (PLMN). In the North American numbering plan, the country code is altered to a typical ten digit format (eleven digits including a “1” prefix considered by many a “North American country code”). A wired telephone typically has a ten digit number in North America having an area code and a seven digit wired line number where the first three digits represent an exchange within an area code.
The MSC for a given service provider then matches the wireless destination telephone number with a so-called location area code or LAC by means of a look-up table memory. A local area identification (LAI) typically represents a mobile country code (MCC), a mobile network code (MNC) and a location area code (LAC). The LAC identifies a location area within a PLMN. The MSC then typically signals the controller, (BSC or RNC), within this LAC to page and locate the called subscriber.
Today, it is known to use the LAC to define an area comprising a number of cells or sectors that may number in the hundreds or even thousands. U.S. Pat. No. 5,649,286 to Frerking issued Jul. 15, 1997, describes location areas associated with the GSM standard in a Background of the Invention section along with associated problems. The LAC typically comprises a large geographical area which may or may not be contiguous. For example, the service provider (PLMN) may be Cingular or Verizon and the LAC defined as the territory covered by that service provider which can be the greater portion of the United States of America. The BSC or RNC then determines all of these hundreds or even thousands of cells or sectors for the LAC during the process of terminating an incoming call to a PLMN subscriber. The BSC or RNC then causes the mobile device to which the call is destined to be paged in each and every one of the hundreds or thousands of cells or sectors associated with the LAC. The object of the page is to locate a given mobile device, referred to herein as user equipment (UE), and to complete the incoming call from the public switched telephone network (PSTN) to the mobile device responding to the page. Mobile device as used herein is intended to include portable devices such as personal devices which may be fixed in a location, receive wireless communications or not, necessarily, be used in a mobile environment such as an automobile. This LAC paging process is defined in third generation (3G) Universal Mobile Telephone Service (UMTS) as well as second generation (2G) Global System for Mobile Communications (GSM) standards and is expected to continue in future versions of such wireless standards.
Typically, a mobile device (UE) may be “off” (no power), “on” (powered) and able to receive calls, or “on” and in a mode of not being set to receive calls. In any “on” state, the mobile device or UE registers with the service provider (PLMN) and, in so doing, the service provider identifies the LAC in which the mobile is presently located. The MSC of the associated wireless service provider records or registers the mobile device in its database as being associated with the LAC in which it registers. This database is referred to as a home location register (HLR). A temporary copy called a visitors' location register may be established if and when a mobile device may roam into a different area served by the HLR. The HLR and its copy, the VLR, may be generally referred to as a location register.
If the mobile device (UE) is in an “off” state, an incoming call to the mobile may be connected to voice-mail, for example, for the wireless subscriber to retrieve later. The mobile device (UE) cannot provide its current location area code (LAC) because it is powered down and unable to receive or transmit registration control signals or respond to a page. A UE in an “off” state is paged from a BSC or an RNC in the LAC in which it last registered.
If the subscriber mobile is “on” and not receiving calls, the subscriber may receive a “missed call” indication and/or an indication of voice messaging. In any “on” status and in a mode of mobile device actuation when a call may be connected or if the mobile is in an “off” state, network resources are wasted in causing paging control signals to be transmitted to hundreds or thousands of cells or sectors from, for example, a base station controller (BSC) or a radio network controller (RNC) to be then rebroadcast from a plurality of base stations throughout a LAC for paging one mobile device or UE.
Recently, standards organizations have defined a service area code (SAC) and a service area identifier (SAI). The SAI is an unique combination of LAC and SAC for a PLMN. The SAC or SAI is smaller than a LAC in terms of the number of cells or sectors it comprises. In particular, in UMTS, an SAC or SAI has been defined at a greater granularity than a Local Area Code (LAC). The SAI, for example, is defined for UMTS third generation (3G) partnership project PP in Technical Specification (TS) 23.003 at section 12.5. The SAI may be provisioned to identify a group of cells or sectors within a LAC as follows: the logical summation of a Public Land Mobile Network (PLMN) given by its identifier (ID), the location area code (LAC) and the service area code (SAC). The SAI defines an area consisting of one or more cells or sectors belonging to the same location area code (LAC). The SAI may comprise, for example, as few as one or a plurality of cells or sectors.
Referring to FIG. 1, there is shown a large circle 100 defining a first LAC or LAC #1 comprising hundreds or even thousands of cells or sectors represented by circles or ellipses 120-1 to 120-n. This LAC 100 may represent the territory covered by a cellular service provider such as Cingular in the United States but is not intended to be so limited. The service provider (PLMN) and LAC#1 of FIG. 1 may be international and represent a service provider in a foreign country. Typically, a LAC is an area comprising a plurality of cells controlled by a controller (RNC or BSC). The LAC#1 may comprise micro-cells or include WiFi LAN's or links and may comprise a location area of any mobile service including newer overlay services such as WiMax to a mobile device (UE), for example, a personal computer or Personal Communications Service (PCS) mobile device (UE).
Each cell or sector shown in FIG. 1 is typically associated with a fewer number of base stations of which eight are shown 110-1 to 110-8 and/or antenna sites covering a group of cells or sectors. For example, a single base station, for example, 110-1, may broadcast to three or up to six cells or sectors, depending on the mobile service standard followed. Again, eight base stations 110-1 to 110-8 are shown in FIG. 1 (110-2 is shown located in cell or sector 120-9) with surrounding cells and sectors (for example, cell or sector 120-8, in which a mobile device 130-4 that needs to be paged is located) as well as the cell or sector in which they are located. A paging control signal typically is broadcast from a common BSC or RNC to each and every cell or sector in LAC#1 100 via the proximate base station. The base station, for example, base station 110-2 then rebroadcasts the paging control signal to its cell or sector 120-9 and surrounding cells or sectors 120-8 in which a registered UE 130-4 may be located at the time of the page.
Notice that FIG. 1, while drawn to suggest that each cell or sector is of the same radius, may comprise cells or sectors of unequal radius or comprise links to premises-based networks, for example, in corporations, universities, airports, private residences and the like. The cells and sectors may overlap, for example, for hand-off purposes for, for example, roaming when a power level of transmission indicates that a hand-off is appropriate from one base station, cell or sector to another as a mobile device (UE) moves. Moreover, a mobile device may move outside a LAC#1 to another LAC for another service provider (a different PLMN-ID) and LAC's for different service providers may overlap.
FIG. 1 shows four registered UE's 130-1 to 130-4 in LAC#1. The four registered UE's 130-1 to 130-4 are proximate to four base stations 110-1 to 110-4. Each registered UE is proximate to a respective base station (or may be located on a border between two cells covered by two different base stations). Nevertheless, FIG. 1 suggests that a UE may have registered in the LAC#1 for a first service provider (with a given PLMN-ID) as well as three other UE's which have registered in the same LAC#1 by way of example and be in a powered up “on” state. So if there are four incoming calls to these “on” and registered four UE, there are required four simultaneous sets of paging control signals for these four UE or up to four times the number of base stations must be paged to complete respective calls. Then, the respective base stations 110 in turn may send up to six paging control signals (depending on how many cells or sectors are covered by a given base station 110) to reach the four UE's 130-1 to 130-4. A PLMN may via a directional antenna equipped base station page a service area code by cell or sector. Consequently, paging by service area code can save use of valuable radio frequency spectrum and conserve power. (According to the prior practices of paging by LAC, a base station would page all its cells and sectors wasting power and spectrum.) Moreover, paging by service area code from a given base station can not only reduce power consumption and conserve spectrum, interference between signal transmissions can be reduced as well. More power and code resources can be allocated to end users, for example, for their data reception (and user data transmission). It may be seen from FIG. 1 that as the number of registered mobile devices increases within LAC#1 100, the resources expended for paging expands almost exponentially.
Also, the larger the LAC area, the greater is the probability of paging congestion. FIG. 1 is greatly simplified showing only eight base stations and less than one hundred cells or sectors. This probability increase is, for example, because the larger the LAC area, the more likely there are even more than four or even four hundred, four thousand or four hundred thousand UE's that are all “on,” registered and must be simultaneously paged, there are hundreds, in deed thousands of base stations per UE that must be signaled and these in turn must send control signals to a multiple, for example, of at least three of the thousands of cells or sectors within their respective antenna reach. Consequently, more paging channels are needed in a paging by LAC environment to address paging congestion and more power and codes will be consumed via paging overhead rather than being allocated to the user for their receipt and transmission of their data.
Nevertheless, FIG. 1 also demonstrates that there exist four base stations 110-5 to 110-8 remote from an “on” registered UE that do not need to broadcast paging control signals that are within the LAC; yet, these base stations will unnecessarily page UE that is not in their reach according to current GSM/UMTS standards. Consequently, there remains a problem in the wireless telecommunication art of paging congestion that requires solution. The opportunity to solve such a problem begins with registration. Provisioning for services at a level of granularity between cell and sector or base station on the one hand and LAC on the other is also a problem in the art. Henceforth in the specification and claims, a cell or sector (terms used similarly in accordance with different mobile standards) shall be referred to as a cell, a radio network controller and a base station controller may be referred to collectively as a controller and a mobile device may collectively refer to either devices which are mobile or fixed but communicate over a wireless link and so include portable devices such as personal communications devices, terminals and computers.